Roof ventilator



June 26, 1962 c. F. JUENG ET AL 3,040,646

ROOF VENTILATOR Filed March 11, 1959 2 Sheets-Sheet 1 F/Gf 22 2 5 ii @lh 1m W 25 24 :5 r24 ll L n NATURAL AIR CURRENT INVENTORS CARL F. JUENG WILLIAM A. MILLER ATTORNEY June 26, 1962 c, F. JUENG ET AL ROOF VENTILATOR 2 Sheets-Sheet 2 Filed March 11 JNVENTORS F. JUENG CARL BY WILLIAM A. MILLER United States Parent- 3,040,646 ROOF VENTHATOR Carl F. Jueng and William A. Miller, Pittsburgh, Pa, assignors to H. H. Robertson Company, Pittsburgh, Pa. Filed Mar. 11, 1959, Ser. No. 798,654 6 Claims. (Cl. 98-43) This invention relates to a roof ventilator and more particularly to a roof ventilator which can operate efficiently either under natural draft or by forced arr flow.

Roof ventilators are employed for exhausting gases and fumes from buildings through openings in the roof. Most of the forced air flow roof ventilators currently in use employ propeller-type fans which are noisy in operation. The noise factor can be offset by the use of less noisy centrifugal fans. Hitherto, however, roof ventilators using the less noisy centrifugal fans have discharged exhaust gases downwardly against the surrounding roof surface, thereby creating undesirable turbulence which creates a back-pressure against the fan and agitates accumulations of foreign material on the roof surface. Where the exhaust gases are of a corrosive nature or in a heated condition, their downward discharge tends to cause deterioration of the roof surface in the area immediately adjacent to the ventilator. Those downwardly discharging ventilators, moreover, do not provide for ventilating action by natural draft.

The principal object of this invention is to provide a roof ventilator which will operate efliciently as a forcedair ventilator by means of a centrifugal fan or under natural draft wherein the exhaust gases are directed vertically upwardly.

A further object of this invention is to provide a weather-proof roof ventilator having a centrifugal fan for exhausting gases in an upward direction.

Another object of this invention is to provide a roof ventilator which will not admit precipitation or foreign materials from the atmosphere into the interior of the building through the ventilator aperture regardless of whether the ventilator is operating under forced draft, under natural draft or is out of service.

Another object of this invention is to provide a roof ventilator which is relatively inexpensive to construct and install.

A still further object of this invention is to provide a roof ventilator which can be readily dismantled in whole or in part for service and maintenance.

According to the present invention, a ventilator opening, surrounded by a curb which rises above the level of the immediately adjacent roof surface, is covered with a tapered curb covering or transition piece which rises as a flueto terminate in a generally horizontal gas orifice through which gases may leave the interior of the building. A centrifugal fan is mounted above the generally horizontal gas orifice and is adapted to rotate about a vertical axis to receive gases from the gas orifice and to discharge them tangentially. A shell is provided to divert the tangentially moving gases into an upwardly flowing stream. Drive means for the centrifugal fan are mounted above the fan in a chamber formed by a dome shaped cover which has an outer rim centrally positioned above the opening at the portion of the shell having the greatest cross-section area, i.e., the central portion of the shell. The lower lip of the shell is positioned beneath the generally horizontal gas orifice yet above and spaced apart from the outer edges of the curb covering. In the described structure, it is possible to define a family of solid geometrical frusta having as one base the upper lip of said shell and having as the other parallel base an imagi nary surface extending through the blades of the said centrifugal fan. It is a feature of this invention that the outer rim of the dome-shaped cover must extend outl ce Patented June 26, 1952 wardly through the most acute frusta which can be constructed as described. I

The invention will be described in detail by reference to the accompanying drawings in which:

FIGURE 1 is a cross-section view of the roof ventiis indicated by the numeral 10. The roof 10 is constructed of structural elements 11 which may include concrete, metal beams, lumber or similar materials of construction. An opening 12 usually of rectangular configuration, is provided in the roof 10. The opening 12 is surrounded by curbing 13 which extends slightly above the upper level of the roof 10. A weatherproof coating or surface 14 is provided above the structural elements 11 to serve a Weatherproof skin over the exposed surface of the building. The coating may comprise tile, cement, bituminous materials, asbestos materials, and the like. The opening 12 communicates with the interior portions of the building from which gases and fumes are to be exhausted. A tapered curb covering 15 or transition piece is provided having a base which is adapted to fit over the curbing l3, and an upwardly tapered central portion terminating in a generally horizontal lip 16, preferably of circular configuration, serving as a gas orifice.

Vertical support elements 17 extend upwardly from the tapered curb covering 15 at points spaced equidistant from the vertical axis thereof. The vertical supports 17 may be secured to the tapered curb covering 15 by any suitable means such as welding, bolting, and the like. A horizontal plate 18 of circular configuration is secured to the vertical supports 17 by means of bolting or welding (not shown). A central opening 2b is provided in the horizontal'plate 18 to receive a rotatable shaft 21 as will be hereinafter described.

A dome 22 of circular cross-section has an outer circular rim 23 which is adapted to be secured to the circularouter edge of the horizontal plate 18. Y

A centrally flared shell 24 is provided, preferably having a circular cross-section, and having an upper lip 25, a wider central portion 26 and a narrower lower lip 27. Means are provided adjacent to the lower lip 27 for securing the centrallyflared shell 24 to the vertical supports 17, for example, bolts 28. Additional brackets 29 may be provided which extend from the horizontal plate 18 to the Wider central portion 26 of the centrally flared shell 25 to increase structural rigidity.

The centrally flared shell 24 may be constructed of metal, such as spun aluminum or sheet steel, or may be constructed of suitable weather-resistant plastic materials. The lower lip 27 is spaced above the outer edges of the tapered curb covering 15 which are outside the lip 16, but below the level of the lip 16. The wider central portion 26 of the centrally flared shell 24 is positioned substantially at the level of the horizontal plate 18. The upper lipv 25 of the centrally flared shell 24 greater than that of the outer This design feature permits removal of the dome 22 without requiring dismantling of the centrally flared outer shell 24.

has an inner diameter Afiixed to a centrally positioned, vertical, rotatable shaft rim 23 of the dome 22.

21 extending through the opening 2i), is a Centrifugal fan 30 which is horizontally rotatable below the horizontal plate 18and above the generally horizontal opening which isthe gas orifice defined by the lip 16. The blades of the atmospheric elements and the efiaust gases. An electric motor 32 having a shaft 33. and a pulley 34 mounted thereon is secured within the chamber 31. A rotatablev shaft 21 is vertically mounted between pillow blocks 35. The upper end of the rotatable shaft 21 is provided with a pulley 36 which may be operatively connected withthe pulley 34 by means of a driving belt 37. The lower end of the rotatable shaft 31 extends through the axial opening 20- and is secured to the centrifugal fan 3%.

'From the foregoing description of the construction of the centrally flared shell 24 it will be apparent that a family of solid geometrical frusta can be constructed having as one base thereof the upper lip 25 and having as the parallel base thereof any horizontal plane extending through the blades of the centrifugal fan 3%. The most acute frustum which can be constructed is indicated by the'line XX of FIGURE 1, extending from the upper lip 25to'the outermost and lowermost tip of the blades of the centrifugal fan 30. It will be noted from inspection of FIGURE 1 that the rim23 of the dome 22 is positioned to the left of the. line. XX, that is, the rim 23 extends outside the most acute frustum described. 7

This feature prevents the entry of precipitation or foreign materials from the atmosphere into the interior of the building. Any drops of precipitation, for example, falling in'the area of the ventilator, must strike either the outer surface of the dome 22 or the inner surface of the centrally flared shell 24. The drops of precipitation ad here to the surfaces and flow downwardly. Those flowing along the inner surface of the centrally flared shell 2.4 drop beneath the lower lip 27. Moisture flowing downwardly over the dome 22 drops from the outer rim 23 thereof onto the lower portion of the inner surface of the centrally flared shell 24 and flows downwardly beneath the lower lip 27. Since the lower lip 27 is spaced above the upper surface of the tapered curb covering 15, as earlier described, the accumulated moisture flows outwardly onto the-upper surface 14 of the roof 10 for disposal along with. other roof accumulated precipitation. Since the lip 16 of the tapered curb covering is positioned above the lower lip 27, any'foreign matter, thus channeled, is prevented from entering the interior of the building through the opening 12. This described weatherproof feature exists regardless of whether the centrifugal fan 30 is operating or not. Frequently adequate ventilation may be provided for a building with the present invention from a natural draft which will be hereinafter described.

Operation In operation of the present roof ventilator, as a forced air ventilator, the motor 32 is energized to rotate the shaft 33 and the pulley 34. The rotary motion is transferred by means of the drive belt 37 to the pulley isfi the vertical shaft 21 and the centrifugal fan 30. Rotation of the centrifugal fan 39 causes gases and fumes to enter the central portion thereof through the opening 12 and the tapered flue covering 15 and the gas passageway defined by. the lip 16' as indicated by the arrows A. The rotatingcentrifugal fan 30 directs the gases and fumes radially outwardly against the inner wall of the centrally flared shell 24 at its central portion 26 as indicated by the arrows B; The gases and fumes are directed upwardly between the dome 22 and the upper lip 25 for discharge into the atmosphere as indicated by the arrows C.

By providing the rim 23 of'the dome 22 at substantially the level of the wider central portion 26 of the centrally flared shell 24, a channel of gradually increasing crosssectional area is provided for the exhaust of gases and fumes whereby substantially all of the vented gases and fumes are discharged upwardly between the dome 22 and the centrally flared shell 24.

If desired, the vertical supports 17 may be extended upwardly above the level of the horizontal plate 18 into the chamber 31. The dome 22- may be fastened to upwardly extending vertical supports of this type.

One or more of the vertical supports 17 may consist of a hollow tube which communicates at its upper end with the chamber 31 and which communicates at its lower end with a source of cooling fluids such as fresh air. The hollow tube thus provides a conduit for cooling fluids to circulate through the chamber 31 to effect cooling of the motor 32.

The construction of the present ventilator permits ventilating action under natural draft during those periods when the centrifugal fan 30 is not operating. As already mentioned, the structure is weather-proof and prevents entry of atmosphericforeign substances into the building.

The natural air currents which move across the top of the ventilator structure may create a natural draft tending to withdraw gases from the building interior for vertically upward removal through the ventilator even when the turbine fan is not operating. The temperature differential existing between the interior of the building and the atmosphere may create a tendency for more interior gaseswardly flanged wind-skip 38 at the upper lip 25- of the centrally flared shell 24, as shown in FIGURE 1 and as clearly illustrated by means of arrows indicating natural air currents in FIGURE 3. The natural air current is caused to jump above the ventilator shell 24 by means of the wind-skip 38 to create by turbulent flow a vortex of reduced pressure above the ventilator.

The preferred embodiment of the present invention already described by reference to FIGURE 1 incorporates in the outer shell 24 an outwardly flared central portion 26 having the greatest innerdiameter'thereof. For facility in transportation. of component elements, it may be desirable to employ an outer shell having substantially straight sidewalls. An alternative embodiment of this construction is illustrated in FIGURE 4 which may illustrates several other alternative constructional details which will be described.

A roof has a ventilator curb 51 defining anopening 52. A tapered curb covering 53 or transition piece terminates in an upper lip 54 which serves as a gas orifice,

for the upward exhaust of gases from the building interror. Vertical support members 55 are securely fastened with respect to the building below the upper lip 54 by means of bolts 56 or other'suitable means. A cylindrical outer shell 57 is secured above the roof 50, preferably to the vertical support members 55. The cylindrical shell 57 has an upper lip 58, a lower lip 59 and has its widest inner diameter in the central portion 60. The 1111161" diameter of the outer shell 57in its central portion 60 is the uniform wide diameter of the straight walls thereof. a

A horizontal plate 61 is, secured to the vertical support members 55 suitably by welding or bolting. A dome shaped cover 62 having an outer rim. 63 is secured above the horizontal plate 61 to define a chamber 64 for confining drive means 65 from which a rotatable shaft extends through the horizontal plate 61 to a centrifugal fan 67. 7 V

In all other respects, the embodiment illustrated in FIG- URE 4 corresponds to the preferred embodiment. Note the line X-X of FIGURE 4 which indicates the most acute frustum which can be formed through the upper lip 58 and the blades of the centrifugal fan 67. The outer rim 63 of the dome shaped cover 62 must extend outside the indicated frustum as before.

FIGURE 5 illustrates schematically onemeans whereby the ventilator of the present invention may be installed in a building having a sloping roof. A building 70 having sidewalls 71 and a sloping roof 72 has a ventilator curb 73 extending vertically upwardly from an opening in the sloping roof 72. The ventilator curb 73 terminates in a generally horizontal opening at its upper end which extends above the upper surface of the roof 72 which is adjacent to the ventilator curb 73. A ventilator 74 according to this invention can be mounted above the open upper end of the curb 73 in the manner described in relation to FIGURE 1.

In some instances, especially where heated or noxious gases are being exhausted, it may be desirable to discharge such gases from a level substantially above the building wherein the gases are generated. As shown in FIGURE 6, such a building 75 may have a stack 76 which is the equivalent of the ventilator curbs already described. A ventilator 77 according to this invention may be installed above the open upper end of the stack 76.

And now according to the provisions of the patent statutes, we have explained the principle, preferred construction and mode of operation of our invention and have illustrated and described what we now consider to represent its best embodiment. However, we desire to have it understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically illustrated and described.

We claim:

l. A ventilator adapted to be mounted above a horizontal opening in the upper surface of a building and communicating with the interior of said building, comprising a transition piece extending across said opening and being centrally upwardly tapered to terminate in a lip defining a generally horizontal gas orifice, a centrally flared shell having a circular upper lip, a central portion and a narrower circular lower lip being disposed about said transition piece such that the said lower lip is below and outwardly separated from said gas orifice but above the outer edges of said transition piece, a centrifugal fan having vertical blades, said fan being mounted above said gas orifice for rotation about a vertical axis, said blades radiating outwardly above and annularly of said gas orifice above a horizontal plane defined by said lower lip and below a horizontal plane through said central portion, drive means for rotating said fan mounted thereabove, a dome-shaped cover for said drive means disposed above said gas orifice and having an outer circular rim positioned substantially at the level of said central,

portion of said shell, said outer rim being of lesser diameter than said upper lip and extending outside the most acute frustum which can be defined by said upper lip and the blades of said fan, said outer circular rim being inwardly spaced from said shell whereby an annular gas flow passageway is provided between said outer circular rim and said shell.

2. A ventilator adapted to be mounted above a horizontal open ventilator curb extending vertically from an upper surface of a building, comprising a transition piece extending from said open ventilator curb inwardly and upwardly to terminate in a lip defining a generally horizontal gas orifice, a plurality of supportelements extending upwardly from points located outwardly from said gas orifice and extending thereabove, a centrally flared shell of circular cross-section having a circular upper lip, a wider central portion and a narrower cir- 5 cular lower lip being disposed about said transition piece such that the said lower lipis secured to said support elements at points which are below and outwardly separated from saidgas orifice but above the outer edges of said transition piece, ahorizontal plate secured to said support elements in the region of said wider central portion, a centrifugal fan having vertical fan blades, said fan being mounted above said gas orifice for rotation on a vertical shaft extending through said horizontal plate, said blades radiating outwardly above and annularly of said gas orifice above a horizontal plane de-' fined by said lower lip and below a horizontal plane through said central portion, drive means for rotating said vertical shaft mounted above said horizontal plate, a dome-shaped cover for said drive means disposed above said gas orifice and having an outer circular rim contiguous with said horizontal plate whereby said domeshaped cover and said horizontal plate define a chamber for said drive means, said outer circular rim being positioned substantially at the level of said central portion of said shell, and being of lesser diameter than said upper lip and extending outside the most acute frustum which can be defined by said upper lip and the blades of said fan, said outer circular rim being inwardly spaced from said shell whereby an annular gas flow passageway is provided between said outer circular rim and said shell.

3. The ventilator of claim 2 whereinthe top of said dome-shaped cover extends in part above aplane defined by the upper lip of said centrally flared shell.

4. The ventilator of claim 2 having structural support brackets extending radially outwardly from said horizontal plate to the central portion of said centrally flared shell.

.5. A ventilator adapted to be mounted above a horizontal opening in the upper surface of a building and communicating with the interior of said building, comprising a transition piece extending across said openingand being centrally upwardly tapered to terminate in a lip defining a generally horizontal gas orifice, a centrally flared shell having a circular upper lip, a central portion and a narrower circular lower lip being disposed about said transition piece such that the said lower lip is below and outwardly separated from said gas orifice but above the outer edges of said transition piece, a centrifugal fan having vertical blades, said fan being mounted above said gas orifice for rotation about a vertical axis, said blades radiating outwardly above and annularly of said gas orifice above a horizontal plane defined by said lower lip and below a horizontal plane through said central portion, drive means for rotating said fan, a cover-plate for said centrifugal fan, said cover plate having an outer circular rim positioned substantially at the level of said central portion of said shell, said outer rim being of lesser diameter than said upper lip and extending outside the most acute frustum which can. be defined by said upper lip and the blades of said fan, said outer circular rim being inwardly spaced from said shell whereby an annular gas fiow passageway is provided between said outer circular rim and said shell.

6. A ventilator adapted to be mounted above a horizontal opening in the upper surface of a building and communicating with the interior of said building, comprising a transition piece extending across said opening and being centrally upwardly tapered to terminate in a lip defining a generally horizontal gas orifice, a shell of said lower lip and below a horizontal plane extending through said central portion, drive means for rotating" said centrifugal fan, a cover plate for said centrifugal 1 References Cited in the file of this patent UNITED STATES PATENTS Fuge May 10, 1949 Solzman Oct. 17, 1950 Jenn Apr. 10, 1951 Gerlitz Feb. 9, 1954 Jenn Mar. 12, 957 Rudy Sept. 10, 1957 Jenn Feb. 18, 1 958 FOREEGN PATENTS Germany May 17, 1954 

